Peritoneal dialysis patient line with sterilizing filter and drain bypass

Abstract

A medical fluid treatment system includes a source of purified water; at least one concentrate for mixing with the water from the source to form a treatment fluid; a disposable set including a pumping portion, a concentrate line in fluid communication with the concentrate source and the pumping portion, and a patient line in fluid communication with the pumping portion, the patient line including a filter having a membrane configured to filter the treatment fluid, the filter configured such that (i) fresh treatment fluid flowing from the pumping portion towards a patient flows through the membrane and (ii) used treatment fluid flowing through the filter from the patient to the pumping portion bypasses the membrane; and a medical fluid delivery machine including a pump actuator operable with the pumping portion of the disposable set.

The invention is claimed as follows: 
     
       1. A filter in which fluid is intended to flow in first and second directions, wherein the filter is configured to filter fluid flowing in the first direction and to not filter fluid flowing in the second direction, the filter comprising:
 a housing; 
 a first fluid pathway provided by the housing for flowing fluid in the first direction; 
 a second fluid pathway provided by the housing for flowing fluid in the second direction; 
 a membrane positioned to filter the fluid flowing in the first direction; 
 an exit end of the first fluid pathway located downstream from fluid flow through the membrane; and 
 a one-way valve located at the exit end of the first fluid pathway, the one-way valve positioned and arranged to prevent fluid flowing in the second direction from reaching the membrane. 
 
     
     
       2. The filter of  claim 1 , wherein the one-way valve is a first one-way valve, and which includes a second one-way valve located at an exit end of the second fluid pathway, the second one-way valve positioned and arranged to prevent fluid flowing in the first direction from flowing through the second fluid pathway. 
     
     
       3. The filter of  claim 2 , wherein the housing includes (i) a first port located downstream from the first one-way valve and in fluid communication with the second fluid pathway and (ii) a second port located downstream from the second one-way valve and in fluid communication with the first fluid pathway. 
     
     
       4. The filter of  claim 1 , wherein the membrane is housed in a membrane housing located within the filter housing and along the first fluid pathway, and wherein the filter housing is configured such that fluid flowing in the first direction flows from outside of the membrane housing, through the membrane, and into an interior region of the membrane housing. 
     
     
       5. The filter of  claim 4 , wherein fluid flowing in the first direction exits the filter from the interior region of the membrane housing and fluid flowing in the second direction bypasses the membrane housing via the second fluid pathway. 
     
     
       6. The filter of  claim 4 , wherein the membrane is a first membrane and which includes a second membrane, wherein the first and second membranes are housed in the membrane housing, and wherein fluid flowing in the first direction is split into a first branch flowing to an outside of the first membrane and a second branch flowing to an outside of the second membrane. 
     
     
       7. The filter of  claim 6 , wherein the membrane housing includes a grid of passageways located between the first and second membranes. 
     
     
       8. The filter of  claim 6 , wherein the first and second membranes are located on opposing sides of the membrane housing, respectively, the first branch extending to a first side of the membrane housing and the second branch extending to a second side of the membrane housing. 
     
     
       9. The filter of  claim 1 , wherein the housing includes a hydrophobic vent for air removal. 
     
     
       10. A disposable set comprising:
 a pumping portion; 
 a fluid line in fluid communication with the pumping portion; and 
 a filter in which fluid is intended to flow in first and second directions, wherein the filter is in fluid communication with the fluid line and is configured to filter fluid flowing in the first direction and to not filter fluid flowing in the second direction, the filter comprising:
 a housing, 
 a first fluid pathway provided by the housing for flowing fluid in the first direction, 
 a second fluid pathway provided by the housing for flowing fluid in the second direction, 
 a membrane positioned to filter the fluid flowing in the first direction, 
 an exit end of the first fluid pathway located downstream from fluid flow through the membrane, and 
 a one-way valve located at the exit end of the first fluid pathway, the one-way valve positioned and arranged to prevent fluid flowing in the second direction from reaching the membrane. 
 
 
     
     
       11. The disposable set of  claim 10 , wherein the pumping portion is part of a disposable cassette of the disposable set, the fluid line extending from the disposable cassette to the filter. 
     
     
       12. The disposable set of  claim 10 , wherein the filter is configured to fluidly communication with the fluid line at different times via the first fluid pathway and the second fluid pathway of the filter. 
     
     
       13. The disposable set of  claim 10 , wherein the fluid line is a first fluid line, and wherein the disposable set includes a second fluid line connected to the filter, the second fluid line for extending to a fluid delivery destination.